Some scholars believe that the Creed promulgated by the First Ecumenical Council was based on an earlier baptismal creed used in Palestine (the Apostles' Creed), while others regard its more likely origin as being a creed issued early in 325 A.D. in Antioch, a so-called "Syrian Creed."

The Coptic church has a tradition that the Nicene Creed was authored by St. Athanasius of Alexandria, whose theology was instrumental at the Nicene council, despite his being only a deacon at the time.

The Creed of Nicea (325 A.D.)

We believe in one God, the Father almighty, maker of all things, visible and invisible;

And in one Lord Jesus Christ, the Son of God, begotten from the Father, only-begotten, that is, from the essence of the Father, God from God, light from light, true God from true God, begotten not made, of one essence with the Father, through Whom all things came into being, things in heaven and things on earth, Who because of us men and because of our salvation came down and became incarnate, becoming man, suffered and rose again on the third day, ascended to the heavens, and will come again to judge the living and the dead;

And in the Holy Spirit.

The Nicene-Constantinopolitan Creed (381 A.D.)

In English:

We believe in one God, the Father Almighty, Maker of heaven and earth, and of all things visible and invisible;

And in one Lord Jesus Christ, the Son of God, the Only-begotten, Begotten of the Father before all ages, Light of Light, Very God of Very God, Begotten, not made; of one essence with the Father, by whom all things were made:

Note: The Nicene-Constantinopolitan Creed as it is recited in Orthodox worship today uses the first person ("I believe..."/"Πιστεύω") rather than the first person plural as it was enacted at the councils.